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drm/i915: fix ilk rc6 teardown locking

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In the failure cases during rc6 initialization, both the power context
and render context may get !refcount without holding struct_mutex.
However, on rc6 disabling, the lock is held by the caller.

Rearranged the locking so that it's safe in both cases.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
This commit is contained in:
Ben Widawsky 2011-03-19 18:14:26 -07:00 committed by Keith Packard
parent 273e27ca80
commit 2c34b850ee
1 changed files with 8 additions and 3 deletions
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11
drivers/gpu/drm/i915/intel_display.c
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@ -6713,13 +6713,14 @@ intel_alloc_context_page(struct drm_device *dev)
struct drm_i915_gem_object *ctx;
int ret;
WARN_ON(!mutex_is_locked(&dev->struct_mutex));
ctx = i915_gem_alloc_object(dev, 4096);
if (!ctx) {
DRM_DEBUG("failed to alloc power context, RC6 disabled\n");
return NULL;
}
mutex_lock(&dev->struct_mutex);
ret = i915_gem_object_pin(ctx, 4096, true);
if (ret) {
DRM_ERROR("failed to pin power context: %d\n", ret);
@ -6731,7 +6732,6 @@ intel_alloc_context_page(struct drm_device *dev)
DRM_ERROR("failed to set-domain on power context: %d\n", ret);
goto err_unpin;
}
mutex_unlock(&dev->struct_mutex);
return ctx;
@ -7295,9 +7295,12 @@ void ironlake_enable_rc6(struct drm_device *dev)
if (!i915_enable_rc6)
return;
mutex_lock(&dev->struct_mutex);
ret = ironlake_setup_rc6(dev);
if (ret)
if (ret) {
mutex_unlock(&dev->struct_mutex);
return;
}
/*
* GPU can automatically power down the render unit if given a page
@ -7306,6 +7309,7 @@ void ironlake_enable_rc6(struct drm_device *dev)
ret = BEGIN_LP_RING(6);
if (ret) {
ironlake_teardown_rc6(dev);
mutex_unlock(&dev->struct_mutex);
return;
}
@ -7323,6 +7327,7 @@ void ironlake_enable_rc6(struct drm_device *dev)
I915_WRITE(PWRCTXA, dev_priv->pwrctx->gtt_offset | PWRCTX_EN);
I915_WRITE(RSTDBYCTL, I915_READ(RSTDBYCTL) & ~RCX_SW_EXIT);
mutex_unlock(&dev->struct_mutex);
}